Designed by the American Board of Forensic Odontology (ABFO), this scale has become the standard for bitemark measurement and photography. The incorporation of three circles is useful in helping to compensate for distortion resulting from oblique camera angles. Graduations are all metric except for the width of the legs, which are 1 wide. The 1cm division lines are traced and extended across the photographic print to grid an image. Measurements within the image are then made relative to these inscribed 1cm grid lines to compensate for any distortion resulting from nonparallelism between the film and the object planes.